Elastic fluid turbine



Oct; 14, 1941. E. D. DICKINSON 2,259,126

ELASTIC FLUID TURBINE Filed July 28, 1959 II {1 22 1' I I 1' I H? I I H O O O O O i I m f 301 25 Invent-0T: Edgar" D. Dickinson,

His Atgorne Patented Oct. 14, 1941 r Gems ELASTIC FLUID TURBINE Edgar D. Dickinson, Beverly, Mass, assignor (to I General Electric Company, ,a corporationjof.

New York Application July 28, 1939, Serial No.: 287,049 (01. 253-69),

3 Claims.

7 The present invention relates to elastic fluid turbines of the type which include a stage having a large-diameter bucket wheel arranged to discharge elastic fluid into another stage having a nozzle diaphragm of small diameter considerably axially spaced from the aforementioned largegdiameter bucket wheel. The large space thus formed between the large-diameter bucket wheel and the small-diameter diaphragm gives rise to considerable loss due to whirling. De- Vices in the form of dams and directing vanes haveheretofore been suggested to reduce this whirling" and smoothly to guide elastic fluid discharged from a large-diameter stage into a small-diameter stage. An arrangement of this kind is described in the application of D. J. Bloomberg, Serial No. 214,909, filed June 21, 1938 and assigned to the same assignee as the present application.

The object of my invention is to provide an improved construction and arrangement of turbines of the type above specified whereby loss in efliciency due to whirling of elastic fluid on its path from a large-diameter stage to a smalldiameter stage is reduced.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 illustrates somewhat diagrammatically a sectional view of a turbine embodying my invention; and Fig. 2 is a view along line 2--2 of Fig. 1.

The multi-stage turbine in the drawing comprises a first stage with a large-diameter first bucket wheel I secured to a shaft II and having an annular row of buckets I2 and a nozzle plate I3 forming a row of nozzles I4 extending over an arc of, for example, 60, thus constituting a partial admission arrangement for elastic fluid to the first bucket wheel I0. The nozzle plate I3 is suitably secured to a casing I5. The latter also forms an elastic fluid chest I6 from which elastic fluid is conducted to the nozzles I4 by a channel II. A second stage of the turbine includes a nozzle diaphragm I8 forming a row of nozzles I9 and supported on the casing I for receiving elastic fluid discharged from the bucket wheel I0 and conducting it to a small diameter bucket wheel 2|] having an annular row of buckets 2|. The shaft II extends through the high pressure end of the casing and is sealed thereto by means of a suitable packing 22.

Details of the packing are not described because they do not form apart'of this invention. r

The second stage, more particularly the nozzles I9 of'the nozzle diaphragm I 8, are considerably axially spaced from the bucket wheel III and the nozzles I9 havea diameter substantially smaller than the diameter of the buckets I2. A large space 23 is thus formed between the bucket wheel I2 and the diaphragm I3 through which 'elastic fluid fioWs on its path from the bucket wheel I2 to the diaphragm I8. i

In order. to (reduce whirling'of'elastic fluid in the space' 23andttoi'mprove the distribution of elastic fluidi'dis'charged from the high pressure stage :to the low' pressure stage; particularly whereielastic fluid is admitted to an arc onlyof the high pressure stage," I provide an annular chamber 2.4 :surrounding'. one" of .the stages, in the present example 7 the low pressure stage, fin- ,cluding the diaphragm I8 and the bucket wheel 20. .Thi's annular chamber .forms in substance an: axial extension; of an outerportion of the space 23. During operation, elastic fluid discharged from the passages formed between the buckets I2 flows into the opposite portion of the annular chamber 24 and is then distributed annularly in the entire chamber 24 to be conducted smoothly to the nozzles I9 of the diaphragm IB. As a further means properly to guide the elastic fluid to the nozzles I9 of the second sta e, I may provide an elastic fluid guiding and directing device 25 with a plurality of vanes 26 forming passages 21 between them for receiving fluids discharged from the passages between the bucket I2 and turning the direction of the flow of fluid axially (see Fig. 2). The guiding device 25 extends over an are which is substantially equal to the arc of admission to the bucket wheel I2 in the present instance about The portion of the bucket wheel which in a particular instant does not discharge any fluid is shielded by a ring 28 secured to, in the present example integrally formed with, the annular nozzle plate I3. From another viewpoint, the nozzle plate I3 forms a chamber 29 for enclosing that portion of the bucket wheel II] to which no fluid is supplied from the nozzle plate. The purpose of the chamber 29 and the shield 28 is to prevent backflow of fluid through the passages formed by the buckets I2 and thus to reduce windage loss and leakage of fluid to the inlet side of the bucket wheel.

During operation fluid discharged from the bucket wheel I2 passes through the passages 21 formed by the guiding device 25 into the annular chamber 24 in which the fluid is distributed annularly and smoothly guided through the space 23 to the nozzles IQ of the diaphragm IS.

The distribution chamber 24 has another important advantage, namely, it permits a reduction of the size of the space 23 between the bucket wheel ill and the diaphragm [8 or, from another viewpoint, it permits closer spacing of the large-diameter bucket wheel l and the small-diameter diaphragm l8 than would be possible without such chamber 24. This closer spacing results in shortening of the axial length of the turbine. spacing is accomplished by a special design. of the diaphragm [8 which has an inner portion or disk 30 closely spaced with the bucket wheel 'III and forming a lateralprojection 3| facing away from the bucket wheel ID to which the inner ends of the nozzle partitions are secured. An outer ring 32 is secured to the outer ends of the nozzle partitions and considerably axially spaced from the bucket wheel, Ill. The outer ring 32 is suitably supported on the turbine casing l5 and surrounds the bucket wheel 20.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Elastic fluid turbine comprising a casing, a first stage having a large-diameter bucket wheel, a second stage including a small-diameter diaphragm and a bucket wheel, the diaphragm comprising an inner disk closely spaced with the first stage bucket Wheel and an outer ring with partitions fastened to the ring and to the disk and considerably axially spaced from the first stage bucket wheel and surrounding the second stage bucket wheel, and a plurality of guide vanes supported on the casing adjacent the diaphragm.

In the present instance the closer 2. Elastic fluid turbine comprising a casing, a first stage having a large-diameter bucket wheel, a second stage including a small-diameter diaphragm and a bucket wheel, the diaphragm comprising an inner disk closely spaced with the first stage bucket wheel and having a lateral projection adjacent the second stage bucket wheel, a ring with a plurality of partitions considerably axially spaced from the bucket wheel and secured to the lateral projection and supported on the casing, and an annular chamber formed by the casing and surrounding the second stage diaphragm and bucket wheel for conducting fluid from the first stage bucket wheel to the diaphragm.

3, Elastic fluid turbine comprising a casing, a first stage having a bucket wheel and a diaphragm for conducting elastic fluid to a part only of the bucket wheel, said diaphragm forming a channel for receiving the portion of the bucket wheel to which no fluid is conducted in order to reduce windage losses, and a second stage comprising a diaphragm of a diameter considerably smaller than that of the first stage bucket wheel, the second stage diaphragm having a disk with an outer rim portion projecting laterally away from the first stage bucket wheel, a plurality of partitions having inner ends secured to said rim portion and an outer ring secured to the outer ends of the partitions and supported on the casing, the disk of the second stage diaphragm being closely spaced with the first stage bucket wheel and the partitions and the ring of the second stage diaphragm being considerably axially spaced from the first stage bucket wheel to form space for conducting fluid to the second stage diaphragm, the casing forming an annular chamber surrounding the second stage for conducting elastic fluid from the first stage to said space.

EDGAR D, DICKINSON. 

